What is the hardest topic to study for CCNA?

[jonhylever]

What is the hardest topic to study for CCNA?

Bridging/Switching
7-layer OSI Model
Routed Protocols (IP)
Routing Protocol (RIP, IGRP etc.)
WAN Protocols (Frame Relay, ISDN, PPP, etc.)
LAN Technologies
Basic Router Management and Configuration
Access Lists

[Deenanath]

If you will ask me then all the above mentioned topics are very easy and i don't seem that any of them will stress you out. But one thing i want to inform you that there is nothing like easy and hard if you have interest in any particular field or subject then you will never feel that particular subject is tough.